Priorly, the microencapsulation of biologically active ingredients has been numerously performed for the objective of increasing the efficacy, decreasing the toxicity or stabilization in pharmaceutical and pesticidal fields. Furthermore, for the field of printing and papermaking, the microencapsulation of pigments or coloring agents has been numerously employed.
As a microencapsulation method, the interfacial polymerization method, In-situ polymerization method, coacervation method, solvent evaporation method, spray-drying method and so on are known.
However, these methods have problems concerning the difficulty of adapting to a solid core, the reluctance to adapt to a comparatively unstable compound, the ease of mixing the solvent utilized during microencapsulation and dissatisfaction with the nature of the obtained microcapsules. None of the methods thereof are sufficient as a microencapsulation method of solids nor was the obtained microcapsule composition itself sufficient.